1. Field of the Invention
The present invention relates to an improvement in igniters for solid fuel rocket motors that has particular utility when leak testing the port seals of the igniter through bulkhead initiators during motor leak tests.
2. Description of the Prior Art
A conventional igniter for solid fuel rocket motors is a miniature rocket motor that is known in the art as a "pyrogen" igniter. Typically, a pyrogen igniter is mounted in the forward end of a rocket motor through a hole in the propellant. The igniter is activated by a through bulkhead initiator, known in the trade as a TBI, that is sealed in a port provided in the bulkhead of the forward closure of the motor. Each through bulkhead initiator includes a detonating cord which translates detonation on the input side which is external of the motor to deflagration on the output side, internally of the motor. The hot gases that are thus produced ignite an ignition charge consisting of ignition pellets. The ignition pellets are contained in a sealed cavity in a sealed end cap at the forward end of the motor.
A problem in solid fuel rocket motors with such igniters has been an inability to leak test the through bulkhead initiator port seal during motor leak tests. This is because the end cap and the ignition charge cavity are sealed and present a barrier to the leak test gas.